Carrying mechanism for calculating



March 7, 1950 J. CARLSEN CARRYING MECHANISM FOR CALCULATING MACHINES Filed Oct. 14, 1946 Patented Mar. 7, 1950 CARRYING MECHANISM FOR CALCULATING MACHINES" John Carlsen, Heller-up, by Copenhagen, Denmark.

Application October 14, 1946; Serial No. 703,249

In Denmark October-'18, 1945 2 Claims. 1

The present invention relates to the carrying mechanism of calculating machines of the type inwhich a carrying mechanism isassociatedwith each row of keys, which carrying mechanism is adapted to be moved against a restoringforceon the depression of the keys, and, in the case of a calculating operation requiring a carry transfer, to be released so as to be permitted tomove back under the influence of the restoring forcethereby influencing the calculating unit of the next higher order.

In machines of this kind, it has been. proposed to arrange for the carrying mechanism to be strained or wound up by means of a spiral cam fixed. to the number wheel, the sp-ral surface of which contacts an arm of the carrying mechanism under the influence of a spring. When the spiral cam is turned the arm is urged backwards against the spring force until the position is reached where the spiral cam has its discontinuity, At this position the arm is suddenly released and permitted to swing back under the influence of the spring, thereby effecting a carrying operation.

This known constructionsufiers from the drawbackthat during the straining of the carrying. mechanism the frictional losses are relatively great as compared with the useful energy, with the result that a comparatively smallincrease of the coeificient of friction as a consequence of wear etc. in the course of time may lead to apoint where the carrying mechanism fails, in which. connection it is to be taken. into account that every carrying mechanism, when released, should be capableof. straining the carrying mechanism of the next higher order to the, extent corresponding to a turning of the number wheel; by one step. Ifv a point is reached. where-the carrying mechanism fails, it will. not be possible' to make the mechanism operate again by increasing the spring force, since practically all thefrictional resistancesto-be overcome-areproportional to the spring force 1 The. present invention is based on. the recognitionthat by arranging for the straining. or wind.- ingrup action. to take. place by meansof intermeshing teeth instead oia spiral cam, the construction. may be-made less sensitive to an increase of the coemcient of.-friction, because. in this manner it. will. be possible to-reducetheproportion. of frictional. losses to useful energy, so

that a. greater increase of the friction is permissible before a point is reached where the carrying mechanism. fails. The invention accordingly providesv for a carrying mechanism in which a toothed-sector is s ci ted wi h.-'t1ie. number 56 2 wheel and adapted, by meshing with teeth on a member of the carrying mechanism, to bring about the above mentioned movement of the latter.

The greater the number of teeth of the two intermeshing toothed sectors is selected, the smaller will be the friction, but on the other hand, the releasing. point of the carrying mechanism will beless well-defined with an increasing number of teeth; but by compromising between these two points. of; view, ithas been found that the most advantageous number of teeth is four, and that in any case the number of teeth should lie within the limit 3-6.

But in order that my invention may be better understood, reference will now be had to the accompanying drawings, inwhich the invention is illustrated as applied to a five key calculating machine, i. e; a machine of the type having keys only for the numerals 1-5 in each column, the addition of the higher numerals being effected by striking twice, e. g. 2x3 instead of 6, 3+4 instead of 7 etc. In said drawings Fig. 1 shows such of the parts of a calculating unit of one order as arenecessary for understanding' the invention, as viewed in cross-sectional elevation along the line II of Fig. 3,

Fig. 2 shows thesame Withthe parts in a different position, and

Fig. 3 shows. the same in plan view.

In the drawings, l l--l 5 are-fivev key arms, each carrying a key representing the numerals. 1-5 respectively. Of these keys only the key 5 representing the amount5 is shown in thedrawing. The key arms H-l5 are arranged in juxtaposi, tionv so as toform a fan-like structure, and all the key-arms are pivotable on a common pivot Hi. The key arm 15 is provided withastud. l1 engaged in. elongated slots l8, I9, 20 and 2|. of. the key arms ll, l2, l3 and 14,. so that on the depressionof any of the keys fixed to the key arms H-l.5, the key arm. It will be swung downwardsonthe pivot IS. The: angle through which each key arm l'l.--l5 is. depressed until striking. thev base of. the machine as. represented at 50 will beproportional to the number represented by the key in. question, and sinceeach. of the key arms. H-M on being depressed carrieswith it the key arm- [.5 through its entire stroke, the angle through which the key arm [5. is moved. will. always be proportional to the number represented by'the depressed key. The detailed. construction. of the. key system. is. the subject-matter of. my co-pending application Ser. No. 628,698, filedon Nov..l5, 1945, nowPatent-No.

ent invention, so that a further description is considered unnecessary for the purpose of the present specification.

The key arm l carries a toothed sector 22, which by way of a gear wheel and a ratchet drive operates a number wheel 24 in such a manner that on the depression of any key the number wheel will be advanced through an angle corresponding to the number represented by the depressed key,

such turning of the number wheel taking place simultaneously with the depression of the key.

At its circumference the number wheel 24 is provided with teeth 26 engaged by a pawl 25 serving to brake the number wheel and to fix it in its predetermined regular positions. The teeth 26 are also engaged by a pawl 42 coupled to a carrying member 21' which co-operates with the calculating unit of the next lower denomination. The carrying member 2'! corresponds exactly tothe carrying member 27 co-operating with the number wheel 24 and serving to carry transfer to the calculating unit of the next higher order each time the number wheel 24 is turned to or past the zero-position.

The carrying member 21 is pivoted at 28 and is loaded by a spring 3i tending to turn it in an anticlockwise direction. In the position shown in Fig. 1 it rests, under the influence of the force of the spring 3|, with an abutment 45 on the edge 43 of a hole 44 in a partition 4| between the considered calculating unit and the calculat ing unit of the next higher order and is thereby fixed in the position shown. The carrying member 27 is provided with a toothed sector 29 adapted to co-operate with a number of projecting teeth 30 on the end of the number wheel 24. The lowermost tooth of the toothed sector 29 is bent out of the common plane of the toothed sector in-a direction towards the number wheel 24, while the other teeth 29b, 29c and 29d of the toothed sector are bent out of said plane in the opposite direction. Similarly, the leading tooth 30a among the teeth 30 of the number wheel is lower, as measured in the axial direction, than the other teeth 30b, 39c and 30d. By this means it is obtained that the teeth 29a and 30a will intermesh in another plane A, Fig. 2, than the plane B in which the teeth 29b, 29c and 29d mesh with the teeth 30b, 30c and 30d.

Behind the toothed sector 29 there is arranged a barring member 32 pivoted at 36 and biased by a torsional spring 37. The construction and operation of the barring member 32 is describedin detail in a co p'e'ndi'ng application Serial -No. 103,247. From'. such"applicatiori it appears that as long as'none of the keys of the numerical group inquestion is'depre'ssed, the barringniember -32 is maintained free of the back edge of-the toothed sector, while oh'--' the-;depressio n' of any key the barring member-is permitted-to turn in such; a direction that adete-nt 38 provided on-the barring member 32 "movestowards the backof the toothed staph and will be capable erqsnapp'ing in behind a shoulder 39' of the toothed sector when thecar- Tying-member 2-1 has reached' a certainposi'tion. T-he position of the number wheel 24 shown in Big. 1 c'orrespondsito the 5" position." In this position the'humber wheel 24 begins to mesh with the toothed sector -29;Qan d when the number wheel is "turned in" an anticlockwise direction by' 'de'pre's' sing one" o'f thekeys of thenumerical group in question; the number wheel willjtherefore', 'cause the carryin member 21 to be'rotat'ed in a clockwise directionagainst the action of the spring 3|, which is" thereby strained er wound up. the teeth 30 preventing the toothed sector 29 and thereby the carrying member 2! from returning to its neutral position under the influence of the spring 3|.

Fig. 2 shows the number wheel in the zero-position immediately after the carrying member has been fully released for return movement. It will be understood that in the zero position the tooth 30d has just slipped off of the tooth 2%, so that the carrying member 2'! may be rotated in an anticlockwise direction under the influence of its spring 3!. However, this rotation of the carryingmember may take place only after the key, the depression of which caused the number wheel to'be rotated to the zero-position, has been restored to normal as shown, because as long as this is not the case the detent 38 will engage behind the shoulder 39 and detain the carrying member 2'! in the position shown.

When the carrying member 21 is turned in an anticlockwise direction under the influence of its spring 3|, it will effect a carry transfer to the numerical group of the next higher denomination by means of a pawl of exactly similar kind as the pawl 42 shown.

In order that the carrying member shall be able to operate in the desired manner, it is necessary that, after having been released, it is permitted to swing altogether back to the position shown in Fig. 1. because otherwise it will .not transfer to the number wheel of the next hi her denomination the full amount of motion necessary for the carrying operation. Accordingly, it is necessary to make certain that the teeth 30a-d cannot get in the path of the teeth 29ad during the return movement of the carrying member 21. This necess tates special measures to be* tak n in two different respects.

First, it is necessary to make clear how far the number wheel may be turned beyond the zeroposition in the same calculating operation that caused it to pass through the zero-position and thereby to in tiate the carrying operation. The extreme position which the number wheel may reach Will occur if, before the operation in question, it was in the 9 posit on and is now turned onwards by depressing the 5 key. This advances the number wheel to the l position, but at the same time a carry transfer may possibly have taken place from the calculating unit of the next lower order, particularly in the case of a multiplication, and if so, the number-wheel-will be advanced to the 5 position inthe operation 'requiring'a carry transfer. Accordingly, provision must be made, whereby the number wheeL-when in its 5"position, does not prevent thecarrying member from moving fully back to-itsnormal position, and this again-means that the teeth 29a and-39a must begin to intermesh-only in'the "5"-positionof-the number-wheel, or at any rate in-theimmediate neighbourhood of same.

Secondly, it must be taken into consideration that in the starting position thus fixed for'the winding-up action ofthe carry transfer'meeha nism; While there is no objection to-the tooth 30a lying in the 'path-ofthe tooth 29a, thetooth 30a must not prevent the teeth 29c, 29d and-29b that arrive first during the return movement of thec'arrying member from passing by. That" is the reason why, according to theinvention, it is proposed to displace the teeth 29a and 30a out of the plane in which the other teeth mesh with each other. If this measure were not taken, it would not be possible to arrange forthe tooth. sueto commence meshing with the tooth 5 immediately in the 5 position, but it would have to be kept a little back so that the windingup or straining of the carrying member would be distributed over a smaller interval.

The employment of a toothed winding-up mechanism leads to the particular advantage that very small frictional losses are encountered. These losses will be the smaller, the greater the number of teeth, but, on the other hand, the release of the carrying member will then be less positive, and by compromising between these two points of view, it has been found that the most favourable number of teeth will be four, and that in any case the number of teeth should lie within the limit 3-6.

The transfer lock controlled by the keys of the lower order in a single transfer mechanism is claimed in my copending application Serial No. 703,247 and the 5-0 transfer drive is claimed in my copending application Serial No. 703,248, now

abandoned, both of which applications were filed concurrently herewith.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed I declare fer member having a first driven-tooth effective 3n in said first plane for engagement with said first driving tooth and having further driven teeth effective in said second plane for engagement with said further driving teeth and located entirely axially outside the path of movement of said first driving tooth, said interengaging teeth forming a tooth drive for moving said transfer member against the action of said biasing spring during part of a revolution of said number wheel of lower order and for thereafter releasing said transfer memberto perform a return stroke, a number wheel of higher order, and means associated with said transfer member for imparting transfer motion to said number wheel of higher order from said transfer member during the return stroke thereof.

2. A five-key calculating machine as set forth in claim 1, said first driving tooth being located entirely outside the path of movement of said first driven tooth in all positions of said number wheel between the 0 and 5 positions thereof.

JOHN CARLSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 548,563 Lenker Oct. 22, 1895 762,521 Felt June 14, 1904 870,184 Krahn Nov. 5, 1907 1,917,732 Petter June 11, 1933 FOREIGN PATENTS Number Country Date 18,545 Great Britain 1892 

